Heat sink assembly

ABSTRACT

A heat sink assembly includes a heat sink and two fixing members. The heat sink includes a board and a number of fins extending substantially perpendicularly up from the board. A first fixing portion and two second fixing portions at opposite sides of the first fixing portion are formed at each of opposite sides of the board. Each fixing member includes a driving portion, a fixing bolt, and two positioning poles. Each driving portion defines an installing hole and two positioning holes at opposite sides of the installing hole. The fixing bolts extend through the installing holes, the first fixing portions, and a circuit board to engage with the circuit board. The positioning poles are inserted into the second fixing portions and the positioning holes. A spring is fitted about each positioning pole and is sandwiched between the corresponding second fixing portion and the corresponding driving portion.

BACKGROUND

1. Technical Field

The present disclosure relates to a heat sink assembly.

2. Description of Related Art

Heat sinks generally define four through holes in corners of boards of the heat sinks, through which four fasteners extend to engage in motherboards, thereby fixing the heat sinks on electronic elements on the motherboards. However, forces for fixing the four fasteners are not always the same. As a result, the board may not contact the electronic element perfectly.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the present embodiments can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present embodiments. Moreover, in the drawings, all the views are schematic, and like reference numerals designate corresponding parts throughout the several views.

FIG. 1 is an exploded, isometric view of an embodiment of a heat sink assembly.

FIG. 2 is a partly assembled view of FIG. 1.

FIG. 3 is an assembled, isometric view of FIG. 1.

FIG. 4 is a cross-sectional view of FIG. 3, taken along the line IV-IV.

DETAILED DESCRIPTION

The disclosure, including the accompanying drawings, is illustrated by way of example and not by way of limitation. It should be noted that references to “an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and such references mean “at least one.”

Referring to FIG. 1, a heat sink assembly is mounted to a circuit board 10. An electronic element 12 is mounted on the circuit board 10. Two fixing holes 14 are defined in the circuit board 10 and at opposite sides of the electronic element 12.

The heat sink assembly includes a heat sink 20 and two fixing members 30.

The heat sink 20 includes a base board 22 and a plurality of fins 24 extending substantially perpendicularly up from a top of the base board 22. Three fixing portions 26 extend out from each of opposite sides of the base board 22, and each fixing portion 26 defines a through hole 28. Distances between two adjacent through holes 28 at a same side of the base board 22 are substantially the same. The three fixing portions 26 can comprise a first fixing portion 26 and two second fixing portions 26 on opposite sides of the first fixing portion 26. The through hole 28 of the first fixing portion is the main through hole 28 and can have a different sized through hole 28 to accommodate the fixing bolts 36.

Each fixing member 30 includes a driving portion 32, two springs 34, a fixing bolt 36, and two positioning poles 38.

The driving portion 32 includes a bar 320 and two tabs 322 connected to opposite ends of the bar 320. The bar 320 defines an installing hole 324 in a center portion. Each tab 322 defines a positioning hole 326.

The fixing bolt 36 includes a connecting pole 360, a head 362 at one end of the connecting pole 360, and a tapered locking portion 364 connected to an opposite end of the connecting pole 360. The locking portion 364 defines a slot in its center. The locking portion 364 is pliable and deforms to extend through the installing hole 324. The head 362 abuts against a top of the bar 320.

An annular blocking portion 382 protrudes from a circumference of each positioning pole 38.

Each spring 34 is fitted about an upper portion of a positioning pole 38 above the corresponding blocking portion 382.

Referring to FIGS. 2 to 4, in assembly of the fixing member 30 to a side of the heat sink 20, bottom ends of the positioning poles 38 are inserted into the outer through holes 28 of a side of the heat sink 20, until the blocking portions 382 abut against tops of the corresponding fixing portions 26. Top ends of the positioning poles 38 are inserted into the positioning holes 326. The springs 34 are sandwiched between the blocking portions 382 and the corresponding tabs 322. The fixing bolt 36 is inserted into the main through hole 28, such that the locking portion 364 deforms through the main through hole 28. After the locking portion 364 passes through the center fixing portion 26, the locking portion 364 restores to abut against a bottom of the center fixing portion 26, thereby fixing the fixing member 30 to the side of the heat sink 20.

The other fixing member 30 is mounted to the opposite side of the heat sink 20 in the same manner. The heat sink 20 is then mounted to the circuit board 10 and is rested on the electronic element 12. The heads 362 are pressed to allow the locking portions 364 to extend through the corresponding fixing holes 14. After the locking portions 364 pass through the circuit board 10, the locking portions 364 restore to abut against a bottom of the circuit board 10. The top ends of the positioning poles 38 extend out of the corresponding positioning holes 326.

Because the heat sink assembly only needs two fixing bolts 36, the risk of operation error is decreased. Additionally, each fixing bolt 36 is spaced from the two corresponding positioning poles 38 substantially the same distance. Therefore, the force applied by the fixing bolt 36 is equally distributed to the positioning poles 38 to make the heat sink 20 evenly contact the electronic element 12.

It is believed that the present embodiments and their advantages will be understood from the foregoing description, and various changes may be made thereto without departing from the spirit and scope of the description or sacrificing all of their material advantages, the examples hereinbefore described merely being embodiments. 

What is claimed is:
 1. A heat sink assembly to be mounted to a circuit board, the heat sink assembly comprising: a heat sink comprising a base board, a plurality of fins extending up from the base board, and two fixing portion sets extending from opposite sides of the base board, each fixing portion set comprising a first fixing portion and two second fixing portions at opposite sides of the first fixing portion, each first fixing portion and second fixing portion defining a through hole; and two fixing members, each fixing member comprising a driving portion, a fixing bolt, two positioning poles, and two springs fitted about the positioning poles, each driving portion defining an installing hole and two positioning holes at opposite sides of the installing hole; wherein the fixing bolts extend through the installing holes and the through hole of the first fixing portions and engage in the circuit board; the positioning poles are respectively inserted into the through holes of the second fixing portions and the positioning holes; each spring is sandwiched between a corresponding second fixing portion and a corresponding driving portion.
 2. The heat sink assembly of claim 1, wherein each first fixing portion is spaced from the corresponding second fixing portions substantially the same distances.
 3. The heat sink assembly of claim 1, wherein each positioning pole comprises an elongated body and a blocking portion protruding from a circumference of the elongated body to abut against a top of the corresponding second fixing portion, and each spring is sandwiched between a corresponding blocking portion and the driving portion.
 4. The heat sink assembly of claim 1, wherein each fixing bolt comprises a connecting pole, and a head and a tapered locking portion connected to opposite ends of the connecting pole, and the locking portion is pliable to extend through the corresponding installing hole.
 5. The heat sink assembly of claim 4, wherein a slot is defined in the locking portion. 